www/apache
1
0
Fork 0
mirror of https://github.com/apache/httpd.git synced 2025-08-07 04:02:58 +03:00
Code Activity

Proxy balancer lbmethods are now registered as providers and not

Browse Source 
via hooks. Move various find() functions back to mod_proxy_balancer
where they belong :)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@279752 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Jim Jagielski
2005-09-09 12:28:02 +00:00
parent cb68a807de
commit 22c5cb4728
4 changed files with 196 additions and 220 deletions
Download Patch File Download Diff File Expand all files Collapse all files

183
modules/proxy/proxy_util.c
View File

@@ -1155,7 +1155,6 @@ PROXY_DECLARE(const char *) ap_proxy_add_balancer(proxy_balancer **balancer,
const char *url)
{
char *c, *q, *uri = apr_pstrdup(p, url);
int i;
proxy_balancer_method *lbmethod;
c = strchr(uri, ':');
@@ -1173,12 +1172,9 @@ PROXY_DECLARE(const char *) ap_proxy_add_balancer(proxy_balancer **balancer,
* NOTE: The default method is byrequests, which we assume
* exists!
*/
lbmethod = (proxy_balancer_method *)conf->lbmethods->elts;
for (i = 0; i < conf->lbmethods->nelts; i++) {
if (!strcasecmp(lbmethod->name, "byrequests")) {
break;
}
lbmethod++;
lbmethod = ap_lookup_provider(PROXY_LBMETHOD, "byrequests", "0");
if (!lbmethod) {
return "Can't find 'byrequests' lb method";
}
(*balancer)->name = uri;
@@ -2069,176 +2065,3 @@ int ap_proxy_lb_workers(void)
lb_workers_limit = proxy_lb_workers + PROXY_DYNAMIC_BALANCER_LIMIT;
return lb_workers_limit;
}
/*
* The idea behind the find_best_byrequests scheduler is the following:
*
* lbfactor is "how much we expect this worker to work", or "the worker's
* normalized work quota".
*
* lbstatus is "how urgent this worker has to work to fulfill its quota
* of work".
*
* We distribute each worker's work quota to the worker, and then look
* which of them needs to work most urgently (biggest lbstatus). This
* worker is then selected for work, and its lbstatus reduced by the
* total work quota we distributed to all workers. Thus the sum of all
* lbstatus does not change.(*)
*
* If some workers are disabled, the others will
* still be scheduled correctly.
*
* If a balancer is configured as follows:
*
* worker a b c d
* lbfactor 25 25 25 25
*
* And b gets disabled, the following schedule is produced:
*
* a c d a c d a c d ...
*
* Note that the above lbfactor setting is the *exact* same as:
*
* worker a b c d
* lbfactor 1 1 1 1
*
* Asymmetric configurations work as one would expect. For
* example:
*
* worker a b c d
* lbfactor 1 1 1 2
*
* would have a, b and c all handling about the same
* amount of load with d handling twice what a or b
* or c handles individually. So we could see:
*
* b a d c d a c d b d ...
*
*/
static proxy_worker *find_best_byrequests(proxy_balancer *balancer,
request_rec *r)
{
int i;
int total_factor = 0;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
proxy_worker *mycandidate = NULL;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: Entering byrequests for BALANCER (%s)",
balancer->name);
/* First try to see if we have available candidate */
for (i = 0; i < balancer->workers->nelts; i++) {
/* If the worker is in error state run
* retry on that worker. It will be marked as
* operational if the retry timeout is elapsed.
* The worker might still be unusable, but we try
* anyway.
*/
if (!PROXY_WORKER_IS_USABLE(worker))
ap_proxy_retry_worker("BALANCER", worker, r->server);
/* Take into calculation only the workers that are
* not in error state or not disabled.
*/
if (PROXY_WORKER_IS_USABLE(worker)) {
worker->s->lbstatus += worker->s->lbfactor;
total_factor += worker->s->lbfactor;
if (!mycandidate || worker->s->lbstatus > mycandidate->s->lbstatus)
mycandidate = worker;
}
worker++;
}
if (mycandidate) {
mycandidate->s->lbstatus -= total_factor;
mycandidate->s->elected++;
}
return mycandidate;
}
/*
* The idea behind the find_best_bytraffic scheduler is the following:
*
* We know the amount of traffic (bytes in and out) handled by each
* worker. We normalize that traffic by each workers' weight. So assuming
* a setup as below:
*
* worker a b c
* lbfactor 1 1 3
*
* the scheduler will allow worker c to handle 3 times the
* traffic of a and b. If each request/response results in the
* same amount of traffic, then c would be accessed 3 times as
* often as a or b. If, for example, a handled a request that
* resulted in a large i/o bytecount, then b and c would be
* chosen more often, to even things out.
*/
static proxy_worker *find_best_bytraffic(proxy_balancer *balancer,
request_rec *r)
{
int i;
apr_off_t mytraffic = 0;
apr_off_t curmin = 0;
proxy_worker *worker = (proxy_worker *)balancer->workers->elts;
proxy_worker *mycandidate = NULL;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
"proxy: Entering bytraffic for BALANCER (%s)",
balancer->name);
/* First try to see if we have available candidate */
for (i = 0; i < balancer->workers->nelts; i++) {
/* If the worker is in error state run
* retry on that worker. It will be marked as
* operational if the retry timeout is elapsed.
* The worker might still be unusable, but we try
* anyway.
*/
if (!PROXY_WORKER_IS_USABLE(worker))
ap_proxy_retry_worker("BALANCER", worker, r->server);
/* Take into calculation only the workers that are
* not in error state or not disabled.
*/
if (PROXY_WORKER_IS_USABLE(worker)) {
mytraffic = (worker->s->transferred/worker->s->lbfactor) +
(worker->s->read/worker->s->lbfactor);
if (!mycandidate || mytraffic < curmin) {
mycandidate = worker;
curmin = mytraffic;
}
}
worker++;
}
if (mycandidate) {
mycandidate->s->elected++;
}
return mycandidate;
}
/*
* How to add additional lbmethods:
* 1. Create func which determines "best" candidate worker
* (eg: find_best_bytraffic, above)
* 2. Create proxy_balancer_method struct which
* defines the method and add it to
* available server methods using
* ap_proxy_add_lbmethods.
*/
PROXY_DECLARE(int) ap_proxy_add_lbmethods(proxy_server_conf *conf)
{
proxy_balancer_method *new;
new = apr_array_push(conf->lbmethods);
new->name = "byrequests";
new->finder = find_best_byrequests;
new = apr_array_push(conf->lbmethods);
new->name = "bytraffic";
new->finder = find_best_bytraffic;
return OK;
}